Blazer driveability

[85 K5]

Do all Blazers command 100% attention while trying to herd it down the road? I have an 85 with 2.5 suspension lift and 32x11.50 tires. Especially when stopping it pulls hard right and during acceleration it goes left. I've had this vehicle for a long time (100,000 miles) and have tried everything I can think of. Ball joints, wheel bearings, power steering gear, rag joint, tie rod ends, all is new. (complete brake job twice)
The only thing I can't correct is the wheelbase is 1 inch difference from one side to the other. Shorter on the right side, measured at spring perches. Is this a problem and will it cause erratic behaviour? If so how can this be corrected?

[Jonboy]

measure to the center of the wheels. If it is off to one side one inch, that will be a problem. It sounds as if one of your lift springs is in backwards. Has the truck ever been wrecked? The right rail might be knocked back. In your brake jobs, did you replace the calipers? My 75 would pull hard to the right during braking, and we found the left caliper stuck. Also, the brake hoses will weaken with age, and are known to collapse during braking, causing a pull.

[Zoomad75]

To answer the original question, no. You shouldn't have to "heard" your blazer down the highway. My 75 has 4" of lift and 35" tires and I can cruise down the highway at posted speeds with one hand on the wheel. It's not a white knuckle ride. Winds are a problem with it having such a high profile, but that's to be expected. Otherwise it's easy to drive.

Your statement about the wheelbase being off is the key. This means either your rear axle isn't square to the chassis or the front isn't. It could be from a wreck as jonboy stated, or the frame is in a diamond shape, or one of the axles sheared a center pin and moved on the spring perch. If it wasn't in a wreck while you owned it I would focus less on the frame and more on the springs/axles.

If the rear axle isn't square to the chassis you have what's called a thrust angle problem. The reason the truck is all over the place is the rear axle is trying to steer the truck in the direction it's pointed. All you can do to drive it is constantly react to the pull. I've driven 30-35ft class A motorhomes with a thrust angle problem and it's madness to drive. It would have to be even worse on a k5 with a much shorter wheelbase.

It might be worth the cost to take it to a shop and have it put on a 4wheel alignment rack. they can measure the thrust angle very quickly. Plus you might need the front end lined up after all the front end work you've done.

If you don't have the cash to have a pro look at it, take measurements from the same points side to side in different spots and compare the readings. If it's just the rear axle that moved you can loosen up the u-bolts and shove the axle back into shape (as long as the center pin is still there).

[85 K5]

Thanks for the replies. Front springs cannot go in backwards. Calipers and hoses were replaced. There is a collision specialist shop here I think I'll take it to and see what they say.

[Jonboy]

Sorry for the simplified reply. Sometimes you don't know the skill level of who you are replying to. I bet there are some folks on here who could get the spring on backwards. Anyhow, Zoomad hit the nail on the head. Doing a front end thrust alignment, the shop can point out any axle setback also. I think I would try that before having it measured at a collision center. It will be a lot cheaper.

Did the problems start after the lift, or did you buy it lifted? I wonder if one of the locating dowels might have sheared off. With the short wheelbase, if there is a problem, it becomes pronounced a lot easier than a longer vehicle. It seems if the frame truly had a diamond, the bumpers would have really funky gaps too, as the center 4 bolts mount directly to the frame. Are the bumpers shimmed from the backside? A "Textbook" diamond will have both bumpers back on one side. It basically changes a ladder frame from a rectangle to a parallelogram, in simplified terms. To have the axle back an inch, it seems like there would be a pretty good buckle in the frame somewhere, or the rail kicked up. Does the fan hit the shroud at all?

[85 K5]

You have brought up some interesting points. I bought it with 150000 miles and it has always driven this way. It was stock, no lift and stock size tires. The lift did not change the way it handled. I have no way of knowing if it was ever wrecked. The fan shroud was broken, though. The rear bumper has taken a light hit, looks like a light pole or something was backed into. Takes a critical eye but it is not straight. (level) Also noticed it was hard to line up the mounting bolts when I put it back on after fuel tank replacement.
The most noticeable aspect is the distance between the tire and fender. On on side I can slide my hand in between tire and fender and on the other side I have to fold my thumb in to get my hand in there. That's when I started measuring the wheelbase.
I like the old beast. all is in great condition and I would like to get it to where I can drive for longer than two hours without being physically worn out.
Taking it to the collision specialist today, I'll let you know what they say.

Thanks!

[Zoomad75]

Well if it drove like crap before and after the lift you put on the frame might be tweaked. Checking by eyeball is one thing, but you are doing the right thing in gettng it measured correctly.

[the_goat]

Could the frame be cracked by the steering box?

[85 K5]

The frame shop told me the frame was as good as new and it hadn't been wrecked. (frame is not cracked at the gearbox) I decided to have the pull when braking checked out. Took it to Brake Check they told me it was the power steering gear. I had one of those high/variable ratio boxes from that place in Dallas or Fort Worth (spinoff of AGR) so I changed that back to a stock box and it drives so much better, almost like a new one. It has been a long list of doing things to correct and make better, I'm not sure which took care of the problem. Probably ball joints. Been running that high ratio for a long time, before and after the ball joints so correcting one problem but had already induced another.........and on and on.......